Focal adhesion of leukocytes to the endothelial lining of blood vessels is a characteristic step in inflammation and in certain vascular disease processes. Although it has long been suspected that alterations in the vessel wall could promote leukocyte adhesion (Cohnheim, J., Lectures in General Pathology. (New Syndenham Society, London) Vol. 1, 2nd Ed. (1898)), until recently, potential mechanisms and modulators of this interaction have remained undefined (Harlan, J. M., Blood. 65:513-525 (1985)). Certain inflammatory/immune cytokines including interleukin-1 (IL-1) and tumor necrosis factor (TNF), as well as bacterial endotoxin, have been shown to act directly on cultured human vascular endothelium to increase the adhesiveness of its surface for blood leukocytes and related cell lines. Bevilacqua, M. P. et al., J. Clin. Invest. 76:2003-2011 (1985); Bevilacqua, M. P. et al., Am. J. Pathol. 121:393-403 (1985); Bevilacqua, M. P. et al., Leukocyte Emigration and Its Sequelae, Movat, H. Z. (ed.), Karger, N.Y., pp. 79-93 (1987); Gamble, J. R. et al., Proc. Natl. Acad. Sci. teu(USA ) 82:8667-8671 (1985); Schleimer, R. P. et al., J. Immunol. 136:649-654 (1986); Dunn, C. J. et al., The Physiologic, Metabolic and Immunologic Actions of Interleukin-1, Kluger, M. J. et al., (eds.), Liss, N.Y. pp. 45-54 (1985); Cavender, D. E. et al., J. Immunol. 136:203-207 (1986); Yu, C.-L. et al., J. Immunol. 136:571 (1986); and Pohlman, T. H. et al., J. Immunol. 136:4548-4553 (1986).
A number of leukocyte and endothelial cell surface proteins participate in endothelial cell-leukocyte adhesion. One example, ICAM-1, is expressed on a variety of hemoporetic cells and non-hemopoietic cells including vascular endothelium. ICAM-1 is a 90 kD glycoprotein which is induced by certain cytokines on endothelial cells. ICAM-1 expression is protein- and mRNA sythesis-dependent and its induction is reversible. Dustin, M. L., et al., J. Immunol. 137:245-254 (1986); Rothlein, R., et al., J. Immunol. 137:1270-1274 (1986); and Pober, J. S., et al., J. Immunol. 136:1680-1687 (1986).
A leukocyte cell surface glycoprotein, LFA-1, is expressed on lymphocytes, granulocytes, monocytes, phagocytes and B cells. LFA-1 also plays a role in leukocyte-endothelial cell adhesion. LFA-1 is a dimeric molecule with a 177 kD (alpha or heavy) subunit and a 95 kD (beta or light) subunit. An F(ab')2 Mab has been developed to the alpha and beta subunits which effectively inhibits leukocyte adhesion to endothelial cells. Mentzer, S. J. et al., J. Cell. Physiol. 126:285-290 (1986); Mentzer, S. J. et al., J. Cell. Physiol. 130:410-415 (1987); and Pohlman, J. H., et al., J. Immunol. 136:4548-4553 (1986).